Carbimazole Tablet: Uses, Dosage, Side Effects, Precautions and Alternates

Quick overview

Carbimazole Tablet contains carbimazole, an anti-thyroid medicine used to treat an overactive thyroid gland (hyperthyroidism). The body converts it into its active form, methimazole, which reduces the amount of thyroid hormones the thyroid gland makes. It is used in adults and children, often alongside other treatments such as surgery, radio-iodine therapy, or beta blockers. Dosage depends on age and thyroid hormone levels, and the medicine carries specific warnings around pregnancy, liver function, and certain serious side effects.

What is Carbimazole Tablet

Carbimazole is an anti-thyroid medicine used to treat an overactive thyroid gland. It is changed by the body into its active form, methimazole, which reduces the amount of thyroid hormones the thyroid gland makes.

Carbimazole Tablet uses

• Treating hyperthyroidism (an overactive thyroid gland) in adults and children
• Controlling excess thyroid hormones that cause weight loss, mood swings, and irritability
• Stabilising thyroid gland function before thyroid surgery
• Used together with other treatments for hyperthyroidism, such as before and after radio-iodine treatment
• Used with beta blockers to manage symptoms like a rapid heartbeat

Benefits of Carbimazole Tablet

• Helps lower thyroid hormone levels and ease symptoms like mood changes, sudden weight loss, and a fast heartbeat
• Can help restore normal thyroid gland function before surgery
• Hyperthyroidism Control: Reduces excessive thyroid hormone production
• Graves' Disease Management: Helps control an overactive thyroid caused by Graves' disease

How Carbimazole Tablet works

After you swallow the tablet, your body converts carbimazole into its active form, methimazole. Methimazole blocks an enzyme called thyroid peroxidase, which is needed to make thyroid hormones. This lowers the amount of the hormones T3 and T4 that your thyroid gland produces.

Carbimazole Tablet dosage

Take the tablets by mouth, swallowing them whole with water. They can be taken before, after, during, or without meals. Your doctor may divide your daily dose into two (morning and evening) or three doses (morning, noon, and night) spaced evenly through the day. The tablet has a score line only to help you break it if you have trouble swallowing it whole, not to split it into equal doses. Do not change your dose without talking to your doctor first. This medicine is not for use in children under two years old.

If you take too much, contact your doctor or nearest hospital emergency department right away and bring the container and any remaining tablets with you. If you forget a dose, take it as soon as you remember; if your next dose is due soon, take both doses together.

Available forms and strengths

Carbimazole is available as a tablet.

Side effects of Carbimazole Tablet

Common

• Nausea/feeling sick
• Headache
• Joint pain
• Mild skin rashes, including nettle rash (urticaria)
• Hair thinning or hair loss
• Itching
• Stomach upset
• Loss of taste
• Drowsiness

Serious

• Signs of infection such as sore throat, fever, or mouth ulcers
• Significant tiredness
• Increased bruising or bleeding tendency
• Feeling generally unwell
• Yellowing of skin or eyes, or dark urine (possible liver problems)
• Muscle pain or weakness
• Nerve pain
• Swelling of lymph nodes or glands in the mouth
• Feeling faint (low blood sugar)
• Kidney problems, such as reduced urine, fluid retention, or blood in urine
• Sudden rash, swelling, or difficulty breathing (allergic reaction)
• Stevens-Johnson syndrome (blistering of skin, mouth, eyes, and genitals)
• Angioedema (swollen tongue, lips, face, or throat)
• Bone marrow depression, which lowers blood cell counts and can become life-threatening if untreated
• Inflammation of the pancreas (acute pancreatitis), with fever or abdominal pain
• Lung problems, such as shortness of breath or cough

Warnings and precautions

• Carbimazole can harm an unborn baby. If you could become pregnant, use reliable contraception during treatment. Tell your doctor if you are or might be pregnant; treatment may need to continue with the lowest possible dose if the benefits outweigh the risks, and may be stopped three to four weeks before your due date.
• You should not breastfeed while using carbimazole, because small amounts of the medicine may pass into breast milk.
• Talk to your doctor before taking carbimazole if you have mild or moderate liver problems. Do not take it at all if you have a severe liver disorder.
• You can drive while taking carbimazole, but do not drive until you know how the medicine affects you.
• Do not take carbimazole if you are allergic to it or any of its ingredients, have a serious blood disorder, have a severe liver disorder, or previously had pancreas inflammation (acute pancreatitis) after taking carbimazole or thiamazole.
• Tell your doctor right away if you get a fever or abdominal pain, as these may be signs of pancreas inflammation, and carbimazole may need to be stopped.
• Carbimazole tablets contain lactose. If you have been told you are intolerant to some sugars, talk to your doctor before taking this medicine.
• Do not stop taking carbimazole on your own without consulting your doctor first, even if you feel unwell.

Storage

• Keep this medicine out of the sight and reach of children
• Do not use after the expiry date shown on the label, carton, or blister after EXP; the expiry date refers to the last day of that month
• Store below 25°C (one source states no special storage conditions are needed; store in the original package to protect from moisture)
• Do not use if you notice any change in the appearance of the tablets
• Do not throw away medicines via wastewater or household waste; ask your pharmacist how to dispose of medicines you no longer use

When to see a doctor

• Stop taking carbimazole and see a doctor immediately if you notice a sudden rash, swelling, or difficulty breathing, which could be signs of an allergic reaction.
• Stop taking carbimazole and see a doctor right away if you get a sore throat, mouth ulcers, high fever, extreme tiredness, easy bruising or bleeding, or feel generally unwell or think you may have an infection.
• Contact your doctor immediately if you notice muscle pain or weakness, nerve pain, swollen glands, feeling faint, or yellowing of your skin or eyes, as these could signal muscle, liver, or kidney problems.
• If you take more carbimazole than you should, contact your doctor or the nearest hospital emergency department right away and bring the container and any remaining tablets with you.

Alternatives

• Methimazole
• Radioactive Iodine
• Beta Blockers